Sökning: "non-linearity"

Visar resultat 1 - 5 av 64 avhandlingar innehållade ordet non-linearity.

  1. 1. Improvement and Assessment of Two-Dimensional Resistivity Models Derived from Radiomagnetotelluric and Direct-Current Resistivity Data

    Författare :Thomas Kalscheuer; Laust B. Pedersen; Christopher Juhlin; Roland Roberts; Heinrich Brasse; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Electromagnetic geophysics; radiomagnetotellurics; direct-current resistivity; displacement currents; dielectric effect; non-linearity; inversion; regularization; two-dimensional model; model variance; model resolution; data resolution; Geophysics; Geofysik;

    Sammanfattning : Two-dimensional (2-D) models of electrical resistivity are improved by jointly inverting radiomagnetotelluric (RMT) and direct-current resistivity (DCR) data or by allowing for displacement currents in the inversion of RMT data collected on highly resistive bedrock. Uniqueness and stability of the 2-D models are assessed with a model variance and resolution analysis that allows for the non-linearity of the inverse problem. LÄS MER

  2. 2. Active Vibration Control of Multibody Systems : Application to Automotive Design

    Författare :Claes Olsson; Alexander Medvedev; Stephen Elliott; Uppsala universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Active Vibration Control; Vibration Isolation; Feedback Control; Adaptive Filtering; Saturation; Limit Cycles; Multi Body Systems; Modelling; Simulation; Non-linearity; Gain Scheduling; Structure Flexibility; Automatic control; Reglerteknik;

    Sammanfattning : Active vibration control to reduce vibrations and structure borne noise is considered using a powerful multi-disciplinary virtual design environment which enables control system design to be considered as an integral part of the overall vehicle design. The main application studied is active automotive engine vibration isolation where, first, the potential of large frequency band multi-input multi-output H2 feedback control is considered. LÄS MER

  3. 3. Characterisation, Modelling and Digital Pre-DistortionTechniques for RF Transmitters in Wireless Systems

    Författare :Mahmoud Alizadeh; Peter Händel; Daniel Rönnow; Noureddine Boulejfen; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RF power amplifiers; non-linearity; memory effects; Behavioral modelling; MIMO; Digital pre-distortion; Electrical Engineering; Elektro- och systemteknik; Intelligent industri; Intelligent Industry;

    Sammanfattning : Wireless systems have become an inevitable part of modern technologies serving humankind. The rapid growth towards large dimensional systems, e.g. LÄS MER

  4. 4. Studies of sound generation and propagation in flow ducts

    Författare :Fabrice Ducret; Mats Åbom; Andy Moorhouse; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; two-port; plane wave; HVAC system; tailpipe; exhaust system; flexible duct; pipe; reflection coefficient; impedance; flow noise; vorticity; damping; scaling laws; impedance; transmission loss; perforated plate; slit; non linearity; Acoustics; Akustik;

    Sammanfattning : This thesis contains three papers investigating problems of interest for noise control in ducts. The first part of this thesis treats the sound propagation in rectangular ducts with flexible walls. Various experimental techniques are performed to measure the internal sound propagation and radiation to the surrounding. LÄS MER

  5. 5. Characterization and Compensation of Hardware Impairments in Transmitters for Wireless Communications

    Författare :Zain Ahmed Khan; Peter Händel; Magnus Isaksson; Mikko Valkama; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Power amplifier; RF transmitters; SISO; MIMO; crosstalk; Volterra series; Volterra kernels; behavioral modeling; DPD; Ramanujan sums; multitone signals; I Q Imbalance; non-linearity; memory polynomial; density estimation; hardware impairments; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Increasing demands for data rate, energy efficiency and reliability in wireless communications have resulted in the introduction of radio frequency (RF) multiple input multiple output (MIMO) transmitters. However, MIMO transmitters suffer from additional crosstalk impairments along with the power amplifier (PA) and I/Q imbalance distortions observed in single input single output (SISO) transmitters. LÄS MER